In automated tomato processing facilities, it is common to process tomato peels after removal from tomatoes by adding acid, such as HCL acid, to the tomato peels and then adding the acidified tomato peel material to a product such as pizza sauce, which needs salt. Tomatoes typically have a pH level of about 4.0, but tomato peel material can have a pH level as high as 13.0 pH when removed by a lye applicator process. It is desirable to lower the pH level, and thus raise the acid level of tomato peel material, closer to approximately the 4.0 pH level of whole tomatoes, so that the peel material is suitable for use in pizza sauces and other commercial food products.
One process for acidifying tomato peels is to introduce batches of tomato peels into an acidification tank, add acid to the peel material, circulate the tomato peels and acid in order to mix the two, and then test the pH of the peel material. If the pH needs adjusting, the appropriate acid level adjustment is made and the material is mixed until the acid level is correct. When the acid level is within an acceptable range, the material is pumped out of the tank and a new batch of tomato peel material is then introduced into the tank to be acidified.
The batch system has several drawbacks, one of which is inconsistent mixing of the tomato peel material and acid, and another of which is a slower than desired processing rate. Full, uniform mixing of the peel material and the acid is not always achieved due to differences in size of peel material chunks and due to the limited extent a circulation system can fully mix the material. In addition, the batch system is inherently slow because the next batch of tomato peel material cannot be acidified until acid level of the current batch is raised to the desired level. The system and process of the present invention seeks to address these problems and provide a continuous system that achieves a quick, uniform acidification rate.